Commit d07be814 authored by Changwoo Min's avatar Changwoo Min Committed by Tejun Heo
Browse files

sched_ext: Add time helpers for BPF schedulers 



The following functions are added for BPF schedulers:
- time_delta(after, before)
- time_after(a, b)
- time_before(a, b)
- time_after_eq(a, b)
- time_before_eq(a, b)
- time_in_range(a, b, c)
- time_in_range_open(a, b, c)

Signed-off-by: default avatarChangwoo Min <changwoo@igalia.com>
Acked-by: default avatarAndrea Righi <arighi@nvidia.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent 2e1ce39f

tools/sched_ext/include/scx/common.bpf.h

+94 −0
Original line number Diff line number Diff line
@@ -408,6 +408,100 @@ static __always_inline const struct cpumask *cast_mask(struct bpf_cpumask *mask) 
void bpf_rcu_read_lock(void) __ksym;

void bpf_rcu_read_unlock(void) __ksym;



/*

 * Time helpers, most of which are from jiffies.h.

 */



/**

 * time_delta - Calculate the delta between new and old time stamp

 * @after: first comparable as u64

 * @before: second comparable as u64

 *

 * Return: the time difference, which is >= 0

 */

static inline s64 time_delta(u64 after, u64 before)

{

	return (s64)(after - before) > 0 ? : 0;

}



/**

 * time_after - returns true if the time a is after time b.

 * @a: first comparable as u64

 * @b: second comparable as u64

 *

 * Do this with "<0" and ">=0" to only test the sign of the result. A

 * good compiler would generate better code (and a really good compiler

 * wouldn't care). Gcc is currently neither.

 *

 * Return: %true is time a is after time b, otherwise %false.

 */

static inline bool time_after(u64 a, u64 b)

{

	 return (s64)(b - a) < 0;

}



/**

 * time_before - returns true if the time a is before time b.

 * @a: first comparable as u64

 * @b: second comparable as u64

 *

 * Return: %true is time a is before time b, otherwise %false.

 */

static inline bool time_before(u64 a, u64 b)

{

	return time_after(b, a);

}



/**

 * time_after_eq - returns true if the time a is after or the same as time b.

 * @a: first comparable as u64

 * @b: second comparable as u64

 *

 * Return: %true is time a is after or the same as time b, otherwise %false.

 */

static inline bool time_after_eq(u64 a, u64 b)

{

	 return (s64)(a - b) >= 0;

}



/**

 * time_before_eq - returns true if the time a is before or the same as time b.

 * @a: first comparable as u64

 * @b: second comparable as u64

 *

 * Return: %true is time a is before or the same as time b, otherwise %false.

 */

static inline bool time_before_eq(u64 a, u64 b)

{

	return time_after_eq(b, a);

}



/**

 * time_in_range - Calculate whether a is in the range of [b, c].

 * @a: time to test

 * @b: beginning of the range

 * @c: end of the range

 *

 * Return: %true is time a is in the range [b, c], otherwise %false.

 */

static inline bool time_in_range(u64 a, u64 b, u64 c)

{

	return time_after_eq(a, b) && time_before_eq(a, c);

}



/**

 * time_in_range_open - Calculate whether a is in the range of [b, c).

 * @a: time to test

 * @b: beginning of the range

 * @c: end of the range

 *

 * Return: %true is time a is in the range [b, c), otherwise %false.

 */

static inline bool time_in_range_open(u64 a, u64 b, u64 c)

{

	return time_after_eq(a, b) && time_before(a, c);

}





/*

 * Other helpers